Electric lamp



L. H. VERBEEK 3,265,922

ELECTRIC LAMP Aug. 9, 1966' Filed Oct. 5, 1961 '2 Sheets-Sheet 1 INVENTOR LEO H. VERBEEK Al lg. 9,1966 L. H. VERBEEK 3,265,922

I ELECTRIC LAMP Filed out." 5, 19s: 2 Sheets-Sheet 2 47 41 1.0 3 as j 39 J lwmwmwml FIG. 2

INVENTOR LEO H.VERBEEK BY M AGEN United States Patent 7,189 4 Claims. (Cl. 313-318) The invention relates to an electric lamp provided with a centre contact and a side contact structurally separated from this centre contact, each of which contacts is connected to one of the current supply wires extending towards the lamp pinch, which lamp further comprises an exhaust tube surrounded by a stem tube.

When the centre contact and the side contact are structurally separated from each other, the advantage is achieved that the construction of one of these contacts is independent of that of the other contact. Thus, in certain cases not only can manufacturing costs be reduced, but also mounting of these contacts may be simplified. As a result, the manufacture of such lamps may be still further mechanized than hitherto.

The present invention relates to an improvement in the centre contact of such an electric lamp. The lamp may be an electric incandescent lamp, but also a lamp in which a discharge tube acts as the light-emitting member. The lamp concerned will generally have a lamp cap which is constructed so that such a lamp may be secured in a screw-holder.

According to the present invention, a lamp of the above-mentioned kind is characterized in that the centre contact of the lamp is supported by a part of the exhaust tube which preferably projects from the lamp vessel. By proceeding in this manner, the advantage is provided that, when designing the parts of the lamp vessel in the proximity of the end of the exhaust tube, such as the end face of the neck of the lamp and its side surface, the construction and the attachment of the centre contact to the lamp need not be considered. Hence, the side contact can be constructed in various ways, which cannot be used in conventional incandescent lamps, since in their design allowance has always to be made for the fact that this side contact must be constructed so that it is possible for the side contact to support the centre. contact. In the method in accordance with the invention, the exhaust tube of the lamp has consequently obtained a new function in the construction of the lamp. When, in accordance with the preferred embodiment of the lamp, the exhaust tube projects from the lamp vessel, the provision of the centre contact thereon does not entail any difficulty.

In a favourable embodiment of the lamp according to the invention, the centre contact consists of a hoodshaped body arranged on the exhaust tube, to which body the end of one of the current supply wires is secured. This hood-shaped body may, for example, consist of a drawn metal sleeve, such as a brass or aluminum sleeve.

In a further embodiment of the invention, the centre contact arranged on the exhaust tube comprises parts which bear on the inner side of the stern tube. In this manner, this body is given a certain lateral support which substantially eliminates the risk of damage to the exhaust tube by transverse stresses.

In a further embodiment of the lamp in accordance with the invention, one of the current supply wires extends within the exhaust tube from the centre contact secured to the exhaust tube towards the lamp pinch. In this manner, the two current supply wires within the stem tube are automatically insulated from each other. In certain cases, no additional precautions need be taken to prevent breakdown between these two wires which 3,265,922 Patented August 9, 1966 may be constructed so as to form a lamp fuse when an arc is struck in the lamp.

For the sake of clarity, it should be noted that, as already stated above, the side contact may be constructed in different manners. This side contact may, for example, consist of a thin metal sheath provided with a helical profile, which sheath may be screwed on the glass lamp neck with the aid of screw-thread which is impressed in this neck.

Alternatively, to such a screw-thread provided in the lamp-neck by pressure an electrically conductive layer may be applied, for example by spraying. The helically wound profile on the lamp-neck may also be rendered electrically conductive with the aid of. a layer of tin oxide. Part of the current supply wire extending along the bulb neck may be connected to such a layer by means of another electrically conductive layer.

It is also possible, to arrange on the screwed part of the lamp-neck an at least superficially electrically conductive foil, which consists of so thin a material that it may be pressed into the profile by means of a suitable tool, for example a roller or a pair of tongs, the material itself then assuming the profile of the neck. Such a foil may consist of brass or aluminum.

The invention will now be described more fully with reference to the drawing.

In the embodiment shown in FIG. 1, one of the current supply wires extends within the exhaust tube.

In the embodiment of FIG. 2, both current supply wires extend in the space between the stern tube and the exhaust tube.

In the lamp of FIG. 1, a filament 2 is inserted into a bulb 1, which filament is secured to the ends of current supply wires 3 and 4. In a pinch 5, these wires terminate in lengths of copper-clad wires 6 and 7. The length of wire 6 extends straight through the pinch into the space between an exhaust tube 8 and a stem tube 9. The wire part 10 concerned is then stretched tautly across an end face 11 of the lamp and passed along a glass neck part 13 provided with screw-thread 12. Then, a part 14 of this current supply wire is disposed between the outer surface of this bulb neck 13 and the inner surface of a thin brass cap 15 screwed thereon. An end 16 of the current supply wire is then bent back and secured to the sheath 15 by means of solder 17.

The length 7 of copper-clad wire is bent over zigzagwise in the pinch 5 so that a second current supply wire 18 secured thereto lies inside the exhaust tube 8. When this part of the current supply wire lying inside the exhaust tube 8 is constructed so as to form a lamp fuse, it is preferably surrounded by an additional close fitting glass tube. This part 18 passes through an end 19 of the exhaust tube 8, which is closed in the usual gas-tight manner and then through a small aperture 20 in a metal cap 21 which bears on the end 19 of the exhaust tube with the interposition of a slight amount of cement. The end of the wire is secured to the outer surface of the bottom of the cap 21 by means of a quantity of solder 22. By a suitable choice of the length of the cap and of the part of the exhaust tube projecting from the lamp vessel, the lamp thus obtained has just the same dimensions as the conventional lamps used for normal lighting.

In the embodiment of the lamp according to the invention shown in FIG. 2, both copper-clad wires 31 and 32 are straight and consequently extend in a pinch 33 in the same manner as in conventional incandescent lamps. Consequently, both wires pass through the space between an exhaust tube 34 and a stem tube 35. A wire part 36, which is secured to the copper-clad wire 31, is in this case also stretched tautly across an end face 37 of the lamp, then guided downwards along the outer surface of a screwed bulb neck 38 and fixed to a conductive layer 40 by means of solder 39, which layer is provided on the screwed lamp neck 38. This conductive layer is provided on the bulb neck, for example, by spraying and may consist of finely divided aluminum. If desired, the bulb neck 38 may be provided with an axially extending recessed part 41 shown in dotted lines, in which the portion of the current supply wire 36 situated on the outer surface of the lamp neck may be disposed.

The other current supply wire 42 is in this embodiment guided along the exhaust tube and clamped between the inner side of a metal sleeve 43 and a sealed end 44 of the exhaust tube 34. This metal sleeve 43 may be secured to the end 44 of the exhaust tube by means of cement. If desired, an intimate contact between the end of the current supply wire and the material of the metal sleeve may thus be achieved, so that it is not necessary for this wire to be soldered to the sleeve. In the embodiment shown,

however, the bottom of the sleeve 43 is provided with an aperture 45 through which the end of the current supply wire 42 passes. This end may be secured to the outer surface of the bottom of the metal sleeve by means of a drop of solder 46.

In this embodiment, the lower end of the sleeve 43 terminates in a flange 47 consisting of insulating material. The outer circumference of this flange bears on the inner side 48 of the conical surface which leads to the space between the exhaust tube 34 and the stem tube 35.

In the usual manner, one or both current supply wires 36 and 42 may be constructed so as to form lamp fuses. Moreover, the space between the stem tube and the exhaust tube may be filled wholly or in part with a material of high quenching activity.

When considering the embodiment shown, it will be clear that the suggested modified construction of the centre contact and the resultant modified construction of the side contact permits of mechanizing the provision of these contacts to a greater extent than in the conventional manufacture of incandescent lamps. Moreover, this lamp construction has the advantage that the complete lamp structure may be manufactured on the machines used hitherto so that any investments for a further automation of the manufacture of the lamps shown are restricted to those parts of the mechanism which serve to provide the finished lamp with a centre contact and a side contact.

What is claimed is:

1. An electric lamp comprising a lamp bulb having a lamp neck including a hollow, annular-shaped stem tube, a filament in said lamp bulb, a center contact, a side contact structurally separate from said center contact, current supply wires connecting said filament with said contacts, a lamp pinch supporting said current supply Wires, and an exhaust tube located in the hollow of said stem tube, said center contact being supported by a part of said exhaust tube.

2. An electric lamp as claimed in claim 1 wherein said center contact comprises a hood-shaped body secured to the free end of said exhaust tube and having the end of one of said current supply wires being connected thereto.

3. An electric lamp comprising a lamp bulb having a lamp neck including a hollow, annular-shaped stem tube, a filament in said lamp bulb, a center contact, a side contact and on said stem tube structurally separate from said center contact, current supply wires connecting said filament with said contacts, a lamp pinch supporting said current supply wires, and an exhaust tube being located in the hollow of said stem tube, said center contact being supported by a part of said exhaust tube and having a metal sleeve over the free end of said exhaust tube and provided with parts bearing on the inner surface of said stem tube, one end of one of said current supply wires being connected to said center contact.

4. An electric lamp as claimed in claim 3 wherein both of said current supply wires are located in the hollow space between said exhaust tube and said stem tube.

References Cited by the Examiner UNITED STATES PATENTS 770,223 9/1904 Cazin 3 l344 X 1,988,290 1/1935 Wright 339-146 X 2,153,398 4/1939 Sittel 220-2.2 X 2,188,298 1/1940 Hitchcock 313242 X 2,950,417 8/1960 Breeding et al 3133l8 X HERMAN KARL SAALBACH, Primary Examiner. ARTHUR GAUSS, GEORGE WESTBY, Examiners. S. CHATMON, JR., Assistant Examiner. 

1. AN ELECTRIC LAMP COMPRISING A LAMP BULB HAVING A LAMP NECK INCLUDING A HOLLOW, ANNULAR-SHAPED STEM TUBE, A FILAMENT IN SAID LAMP BULB, A CENTER CONTACT, A SIDE CONTACT STRUCTURALLY SEPARATE FROM SAID CENTER CONTACT, CURRENT SUPPLY WIRES CONNECTING SAID FILAMENT WITH SAID CONTACTS, A LAMP PINCH SUPPORTING SAID CURRENT SUPPLY WIRES, AND AN EXHAUST TUBE LOCATED IN THE HOLLOW OF SAID STEM TUBE, SAID CENTER CONTACT BEING SUPPORTED BY A PART OF SAID EXHAUST TUBE. 